MAOB and Parkinson disease: Included in these studieswere KW-6002, a potent A2A receptor antagonist (Ki of 2.2 nM) which isundergoing clinical trials for PD, and (E)-8-(3-chlorostyryl)caffeine (CSC), which has been shown to be neuroprotective in the MPTP Parkinsonianmouse model.58 All of thecompounds tested in the studies by Petzer et al.57 showed MAO-B inhibition in the low micromolarto high nanomolar range, with the Ki of KW-6002 at 21 μM, and that of CSC at0.1 μM.